I got chatting to a lovely lady over the weekend who explained to me why the base of some columns in churches are shiny. Originally there wouldn't have been any seats for the congregation and people would perch whereever they could find a suitable spot. Over time the lanolin from their woollen clothes leached into the stones of the columns producing the shiny effect. Having been absorbed over many years into the stone it can't then be removed. I do so love a snippet of social history.